1. Technical Field
The present invention relates to a liquid ejecting head having a piezoelectric element that includes a first electrode, a piezoelectric layer, and a second electrode and causes changes in the pressure in pressure-generating chambers communicating with nozzle orifices. The invention also relates to a liquid ejecting apparatus and a piezoelectric element.
2. Related Art
A piezoelectric element used in a liquid ejecting head is formed of two electrodes and a piezoelectric material sandwiched therebetween that has a function of an electromechanical transducer, for example, a piezoelectric layer composed of a crystallized dielectric material. Such a piezoelectric element is, for example, mounted in a liquid ejecting head as an actuator that operates in a flexural oscillation mode. A typical example of a liquid ejecting head is, for example, an ink jet recording head in which a pressure-generating chamber communicating with a nozzle orifice that discharges ink droplets is partly formed of a diaphragm. The diaphragm is deformed by the piezoelectric element and thereby applies pressure to the ink in the pressure-generating chamber to discharge an ink droplet from the nozzle orifice. One example of such a piezoelectric element mounted in an ink jet recording head is formed by the following process: a first electrode film is formed on one surface of a substrate (passage-forming substrate) by sputtering or another method; a piezoelectric layer composed of lead zirconate titanate (PZT) or the like is then formed on the first electrode film by a sol-gel process or a liquid phase method such as a metal-organic decomposition (MOD) method; a second electrode is formed on the piezoelectric layer by sputtering; and the piezoelectric layer and the second electrode are patterned (refer to JP-A-2006-093312, for example).
The arrangement of such piezoelectric elements has become more and more dense to improve the printing quality. Recently, further densification has been desired; however, a very dense arrangement of piezoelectric elements requires a reduction in the size of each piezoelectric element. This poses a problem in that necessary piezoelectric properties (amount of deflection) cannot be obtained for a size-reduced piezoelectric element. Therefore, a piezoelectric element that can achieve a greater deformation with a relatively small drive voltage is required. It is to be noted that this is a problem not only in liquid ejecting heads, representative examples of which being ink jet recording heads, but also in piezoelectric elements that are mounted in other apparatuses.